Try these I don't know for certain if they do Coventry Die head cutters but it is worth a call.

https://www.abbcotooling.co.uk/

David

I have both the Alfred Herbert No1 and No2 Fixtures that should do up to the 31/2" dies though The info for the No2 does not mention 11/4", only listing 3/4", 1", 21/2" and 31/2" FT dies. It will regrind the throat and also the rake angle if needed.I have the height gauges. May be some one can answer the question as to IF this device will do your dies. If yes then we are part way to solving the problem. The device is new and I have never used it ! There is a No3 I believe. Noel.

DC31K, thanks I have the Alfred Herbert book on the coventry die heads, there were many editions, the early ones did not cover the later device for regrinding. The wiseman section I will look at. Thanks. Noel.

PS, just looked at the wiseman site it is a copy of the later Herbert book and has answered the question ! You need the No3 device to do 1 1/4" die head chasers. Thanks again.

Edited By noel shelley on 08/08/2022 22:59:03

To clarify, you need more than just those grinding fixtures.

You also need a surface-grinder or tool-&-cutter grinder to use them on.

Mine, marked "3/4 RH" on top and with the Alfred Herbert name embossed in a recess underneath, definitely is. It does not appear to have a number though; just size and thread-hand.

The idea is to grind the set of 4 as a unit. It may be possible to make some form of grinding-jig to sharpen them one at a time on a bench-grinder; but it is vital that the grinding is accurate enough for the set still to work together. Each chaser must pick up exactly a quarter-pitch beyond where its previous one left off.